1. Field of the invention
The invention relates to communication networks and more particularly to optimizing communication network operation and/or configuration.
2. Description of the Prior art
Because of communication network deployment and operating costs, it is beneficial for communication network operators to optimize network operation and/or configuration frequently. This can enable them to make the best use of the communication resources of their network, in particular taking account of service level agreements that they have entered into with their users, and/or to densify or expand a network.
Optimizing a network and thus managing the use of its resources requires network operation and/or configuration data, referred to as analysis data, for example traffic data that defines the traffic passing through the network elements and network parameters or indicators, for example quality of service (QoS) indicators.
The person skilled in the art is aware that network parameter (or indicator) management is difficult and complex and also continuous in the event of network expansion and/or densification. It necessitates the use of a network optimization system (or tool) such as the Radio Network Optimization (RNO®) system for cellular radio networks developed by Alcatel. A system of this kind can be used to track changes in the quality of service (QoS) in certain network elements, for example cells, to diagnose the causes of problems, in particular quality of service problems, and to propose solutions to those problems.
Some diagnostic tools, including the RNO® tool, use diagnostic trees to produce diagnoses and thus to determine the root causes of a problem. A diagnostic tree is a structure consisting of nodes each associated with one or more tests or analyses of a network under study and linked to each other by branches representing logical relationships between tests called causality relationships. The leaves (or terminations) of a diagnostic tree correspond to particular causes of a problem (causes explaining the origin of a problem), the parent nodes of those leaves correspond to the causes of those particular causes, and so on until the root node of the tree is reached that corresponds to a root cause corresponding to the root problem to be explained.
To determine each particular cause at the origin of a problem (its root cause), the diagnostic tool works up the diagnostic tree that corresponds to that problem from its root node to one or more of its leaf nodes. The test results at each node along the way are deemed to enable each cause of a problem to be determined accurately, in order to be able to solve the problem effectively.
These diagnostic trees are very powerful. However, because the networks are very complex, they are generally very complex to design and to use and it is often difficult to exploit their results.
Moreover, diagnostic trees are rarely the optimum when they are first used in a network, in particular because it is difficult, if not impossible, to test them when they are in progress, given the number of analysis values that must be taken into consideration. Because of this, experts must regularly optimize the diagnostic trees in order to improve their accuracy and enable appropriate corrective action. This optimization, requiring the analysis of very large numbers of diagnostic reports (delivered by the diagnostic tool) and an in-depth knowledge of the operation of the network concerned, can be lengthy and thus delay the discovery of the origin of a network problem and the implementation of the corresponding solution.
Thus an object of the invention is to improve upon this situation, in particular in the case of radiocommunication networks.